1. Field of the Invention
This invention relates to a gas discharge panel providing a function of shifting or scanning a discharge spot, and especially to an improvement in pulse driven self-shift plasma panels for information display and/or memory.
2. Description of the Prior Art
As an example of a gas discharge display panel, an AC driven plasma display panel having a matrix type electrode arrangement is well known. However, this matrix type plasma display panel has the drawback that a complicated driving circuit is required in order to address individual discharge cells in the discharge gap at the intersection points of electrodes arranged transversely in the horizontal and vertical directions on the two substrates, and the cost of such driving circuits drastically increases with increase in size of the panel. Thus, a "self-shift plasma display" gas discharge panel providing a discharge spot shifting function was developed to simplify the driving circuitry for some applications.
The typical configuration of such self-shift plasma display is described in detail in U.S. Pat. No. 3,944,875, "Gas Discharge Device Having a Function of Shifting Discharge Spots" by Owaki et al, assigned to the same assignee as that of this invention. According to the disclosure of this U.S. Pat. No. 3,944,875, the self-shift plasma display includes common electrodes arranged in the horizontal direction (Y) and coated with a dielectric layer on one substrate, and a plurality of shift electrodes arranged in the vertical direction (X) and also coated with a dielectric layer on the other substrate. The shift electrodes are periodically and sequentially connected to three or more busses and lead out to common terminals, respectively, thereby resulting in the shift channel having a periodic cell arrangement with respect to the common electrodes. Moreover, at one end of the shift channel, the write electrode for inputing the display information is provided. Thus, in such a self-shift plasma display, the discharge spots generated by information input to the write electrode can be shifted sequentially to the adjacent discharge cells by making use of the priming effect due to the plasma couple by sequentially switching the shift voltage via the busses.
However, the above-mentioned self-shift plasma display panel of the crossing electrode type requires that several shift electrodes must be connected sequentially to at least three busses on one substrate. In this connection of the common electrodes to each buss, the crossing area between at least one buss and the shift electrode conductor to be connected to the at least one other buss must be insulated, requiring troublesome crossover techniques. Formation of this crossover area not only impedes yield of panel fabrication and improvement of reliability, but also makes the pitch of the shift electrodes small, significantly hindering realization of high resolution display.
On the other hand, U.S. Pat. No. 3,775,764 to J. P. Gaur entitled "Multi-Line Plasma Shift Register Display", discloses a panel configuration with a different type of self-shift plasma display, wherein several parallel shift electrodes are oppositely arranged in zig-zag at the internal surfaces of a pair of substrates and these shift electrodes are grouped into two groups on each substrate. According to this self-shift plasma display of the parallel electrode type, the drawback accompanying the formation of crossover areas described above is resolved, but a new problem as to discharge spot isolation arises which also impedes high resolution display.
Moreover, other prior art plasma display panels having the function of shifting the discharge spot are described in U.S. Pat. No. 3,704,389 to W. B. McClelland, entitled "Method and Apparatus for Memory and Display." In this prior art, shift electrodes of a special pattern are used in order to shift the discharge spots by making use of the expanding phenomenon of wall charges to the adjacent discharge wall. And, the shift channel is formed by said shift electrodes having a special pattern. However, the self-shift plasma display involved in this prior art is not practical in that plasma coupling between adjacent cells is not considered and therefore it is very difficult to obtain the operating margin required for commercial use.